A156776 - cp's OEIS frontend

A156776 Number of iterations of x->(sigma(x)+phi(x))/2 until a non-integer is reached when starting with x=n; a(n)=0 if this never happens.

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	0
7	0
8	1
9	1
10	0
11	0
12	2
13	0
14	3
15	2
16	1
17	0
18	1
19	0
20	2
21	0
22	0
23	0
24	4
25	1
26	0
27	0
28	4
29	0
30	0
31	0
32	1
33	4
34	3
35	2
36	1
37	0
38	0
39	0
40	0
41	0
42	9
43	0
44	0
45	0
46	0
47	0
48	7
49	1
50	1
51	0
52	0
53	0
54	8
55	3
56	2
57	0
58	0
59	0
60	0
61	0
62	8
63	7
64	1
65	0
66	0
67	0
68	0
69	7
70	6
71	0
72	1
73	0
74	0
75	0
76	4
77	6
78	5
79	0
80	0
81	1
82	0
83	0
84	5
85	6
86	5
87	4
88	3
89	0
90	9
91	0
92	0
93	7
94	6
95	5
96	4
97	0
98	1
99	9
100	1
101	0
102	5
103	0
104	9
105	3

[0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 2, 0, 3, 2, 1, 0, 1, 0, 2, 0, 0, 0, 4, 1, 0, 0, 4, 0, 0, 0, 1, 4, 3, 2, 1, 0, 0, 0, 0, 0, 9, 0, 0, 0, 0, 0, 7, 1, 1, 0, 0, 0, 8, 3, 2, 0, 0, 0, 0, 0, 8, 7, 1, 0, 0, 0, 0, 7, 6, 0, 1, 0, 0, 0, 4, 6, 5, 0, 0, 1, 0, 0, 5, 6, 5, 4, 3, 0, 9, 0, 0, 7, 6, 5, 4, 0, 1, 9, 1, 0, 5, 0, 9, 3]

cp's OEIS Frontend

A156776 Number of iterations of x->(sigma(x)+phi(x))/2 until a non-integer is reached when starting with x=n; a(n)=0 if this never happens.

Table of values

List of values

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	0
7	0
8	1
9	1
10	0
11	0
12	2
13	0
14	3
15	2
16	1
17	0
18	1
19	0
20	2
21	0
22	0
23	0
24	4
25	1
26	0
27	0
28	4
29	0
30	0
31	0
32	1
33	4
34	3
35	2
36	1
37	0
38	0
39	0
40	0
41	0
42	9
43	0
44	0
45	0
46	0
47	0
48	7
49	1
50	1
51	0
52	0
53	0
54	8
55	3
56	2
57	0
58	0
59	0
60	0
61	0
62	8
63	7
64	1
65	0
66	0
67	0
68	0
69	7
70	6
71	0
72	1
73	0
74	0
75	0
76	4
77	6
78	5
79	0
80	0
81	1
82	0
83	0
84	5
85	6
86	5
87	4
88	3
89	0
90	9
91	0
92	0
93	7
94	6
95	5
96	4
97	0
98	1
99	9
100	1
101	0
102	5
103	0
104	9
105	3

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	0
7	0
8	1
9	1
10	0
11	0
12	2
13	0
14	3
15	2
16	1
17	0
18	1
19	0
20	2
21	0
22	0
23	0
24	4
25	1
26	0
27	0
28	4
29	0
30	0
31	0
32	1
33	4
34	3
35	2
36	1
37	0
38	0
39	0
40	0
41	0
42	9
43	0
44	0
45	0
46	0
47	0
48	7
49	1
50	1
51	0
52	0
53	0
54	8
55	3
56	2
57	0
58	0
59	0
60	0
61	0
62	8
63	7
64	1
65	0
66	0
67	0
68	0
69	7
70	6
71	0
72	1
73	0
74	0
75	0
76	4
77	6
78	5
79	0
80	0
81	1
82	0
83	0
84	5
85	6
86	5
87	4
88	3
89	0
90	9
91	0
92	0
93	7
94	6
95	5
96	4
97	0
98	1
99	9
100	1
101	0
102	5
103	0
104	9
105	3

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	0
7	0
8	1
9	1
10	0
11	0
12	2
13	0
14	3
15	2
16	1
17	0
18	1
19	0
20	2
21	0
22	0
23	0
24	4
25	1
26	0
27	0
28	4
29	0
30	0
31	0
32	1
33	4
34	3
35	2
36	1
37	0
38	0
39	0
40	0
41	0
42	9
43	0
44	0
45	0
46	0
47	0
48	7
49	1
50	1
51	0
52	0
53	0
54	8
55	3
56	2
57	0
58	0
59	0
60	0
61	0
62	8
63	7
64	1
65	0
66	0
67	0
68	0
69	7
70	6
71	0
72	1
73	0
74	0
75	0
76	4
77	6
78	5
79	0
80	0
81	1
82	0
83	0
84	5
85	6
86	5
87	4
88	3
89	0
90	9
91	0
92	0
93	7
94	6
95	5
96	4
97	0
98	1
99	9
100	1
101	0
102	5
103	0
104	9
105	3